This invention relates to the chemical modification of polyalkoxy siloxanes by reaction with alcohols and to useful applications of the products. This reaction with alcohols makes it feasible to produce numerous polysiloxanes with new properties and to customize the chemical structures for specific applications. In particular, the invention focuses on “hydrophilic silicones,” i.e., polysiloxanes substituted with hydrophilic groups, for imparting hydrophilic properties, or if the degree of substitution is sufficient, resulting in water solubility.
Liquid silicone polymers, such as polydimethoxylsiloxane, have a very low solubility in water or aqueous solutions. In order to accommodate this property, they can be emulsified with the aid of surfactants in order to form aqueous emulsions, possibly stable for long periods or even indefinitely. Such emulsions consist of a suspension of very small droplets of liquid silicone, perhaps visible microscopically, but more easily characterized and monitored by light scattering. Despite the inherent instability of most emulsions, many cosmetics products are successfully based on emulsification. This has resulted from extensive experimentation in selecting the optimal surfactant and in confirming the emulsion stability of the product over an appropriate time period.
In order to provide water soluble silicones, there have also been prior art methods to chemically modify the silicone structure to circumvent the need for emulsification. These include dimethicone polyols (Siltech), cyclomethicones (Clearco) and polyesters (Zenitech). In contrast to the inventive goals, the reaction between alcohols and alkoxysiloxanes has been used to introduce hydrophobic properties; wood contains hydroxyl groups and, as a finely divided flour, has been reacted with oligoethoxysilioxanes to produce a solid material with low water affinity and compatibility with hydrocarbon polymers.